I say run it. Remove the rear PV, jet it up and use extentions in the back. Start tuning from there. I did one this summer for my 406 in a 64 Malibu and it runs real crisp. I had mine about 25 years, didn't like it when I bought it (mostly because I didn't understand how to tune a carb, well, I still don;t that well but I'm learning) in any case it was still like new being bagged and oiled all these years.Mine is a street/strip pump gas deal so maybe some differences from what you want but I drilled and tapped all air bleeds and the IFR in the lower pos. I'm still tunning on it but so far I've gone from .037 IFR to a .032, an .066 IAB to a .070, stock .026 MAB, stock PVCR of .067, 73 PMJ, 86 SMJ, stock 31 squirters, blue cam on primary, the emultion package seems to work good without mods. I now have a steady idle 950 RPM in gear @ 13 to 1 AFR, 14.5 to 15 AFR cruise and 12.6 WOT. One other thing I had to grind down the secondary cam to start to open the secondarys a little later.Motor is 10.3 to 1, 240@.050 solid roller, 1.6, AFR 210 comp. timing 20* bal. 16* mech. 12*port vac.

I reworked it this weekend, it was all kinds of messed up, No jet extensions, rear barrels were not opening all the way. They couldn't get it to idle below 2000 rpms.

I went through it and drilled for all screw in bleeds. It idles at 1300 now, pulls down to a 1000 in gear. Carb is alot more responsive now. Really curious to see how it runs this weekend. Based on what I found and did, I think my buddy is going to be in for a nice surprise.

It is a 406, its in a 2100 pound rodster. This is my buddys first racecar so he wanted something mild. It ran a best of 6.58@103. Suppository this motor was running 5.50s in a dragster. I don't think its a 5.50 motor, but I do think the carb work should help it, based on what I found.

Sence we are working on the same size motor would you mind if I asked what compression, cam, intake and heads it has? Was the 2100 lbs with or without driver? Thanks. Also do you know what the digger weighed.

Regarding the motor, to be honest, we are not sure exactly how it is setup. He got it real cheap and was told it was running 5.50s in a dragster. I don't believe that. I now it has a bowtie intake, world heads, I measured the cam and it is around 555 lift with 260 duration. I believe 2100 pounds was with the driver.

He was told this carb was run on the dragster that ran 5.50s, but yet this carb had no jet extensions and powervalves front and back. So unless they ran it sideways, I am not buying it. Pulled the valve covers off and it has all different types of rocker arms. Granted he paid 2k for the motor so what can you really expect for a high performance.